Accidents from tumbling over or falling frequently occur in infants and elderly persons due to low cognitive ability. Thus various techniques are proposed in order to prevent such accidents, and products are being marketed for the prevention of accidents.
For example, Patent Literature 1 describes a disadvantaged-person support system that allows a disadvantaged person, such as a child, elderly person, or physically disabled person, to avoid danger by using a portable terminal to warn the disadvantaged person of danger when the disadvantaged person approaches or enters a dangerous location. Moreover, Patent Literature 2 describes a fall-prevention device that, by use of a weight sensor installed on a veranda, detects danger of a person falling from the veranda.